Poster Presentation Cancer Survivorship 2019

The impact of attrition on longitudinal, patient-reported health-related quality of life among colorectal cancer survivors participating in the PROFILES registry (#222)

Imogen Ramsey 1 , Belle de Rooij 2 3 , Floortje Mols 2 3 , Nadia Corsini 1 , Nicole Horevoorts 2 3 , Marion Eckert 1 , Lonneke van de Poll-Franse 2 3 4
  1. Rosemary Bryant AO Research Centre, University of South Australia, Adelaide, Australia
  2. The Netherlands Comprehensive Cancer Organization, Utrecht, The Netherlands
  3. Department of Medical and Clinical Psychology, CoRPS – Center of Research on Psychology in Somatic Diseases, Tilburg University, Tilburg, The Netherlands
  4. Division of Psychosocial Research and Epidemiology, The Netherlands Cancer Institute, Amsterdam, The Netherlands

Aims

A ubiquitous challenge in longitudinal oncology research is attrition and subsequent missing data. This study aimed to determine the rate of and factors associated with attrition in the PROFILES registry among a cohort of colorectal cancer survivors, and to assess the impact of attrition on observed health-related quality of life (HRQOL) estimates.

Methods

Sociodemographic, clinical and patient-reported outcome (PRO) data was collected annually from a cohort of 2625 colorectal cancer survivors participating in PROFILES between 2010 and 2015. Sociodemographic and clinical characteristics according to time of dropout were compared using analysis of variance and chi-square tests. Predictors of attrition were examined in logistic regression analysis comparing full response and dropout. Multilevel linear mixed models were constructed to investigate associations between attrition and HRQOL over time.

Results

Colorectal cancer survivors who were women, elderly, had low or medium socioeconomic status, had low education, and reported depressive symptoms were more likely to drop out. Full responders reported better and more stable HRQOL than participants who dropped out after the first or second wave. Over time, participants who dropped out after the second, third or fourth wave showed a steeper decline in global HRQOL and physical functioning and a steeper increase in depression than full responders. Participants who dropped out after the third or fourth wave also showed a steeper decline in social functioning, emotional functioning and the summary score. Sensitivity analyses suggested this trend was driven by mortality.

Conclusions

Although attrition is not fully preventable, additional strategies to retain participants at risk of attrition due to illness could improve the representativeness of future studies. Using appropriate methodological and statistical techniques to account for attrition and missing data will facilitate the interpretation of findings in longitudinal PRO research.